Re-enable PC updates for indexed properties

A previous change reverted behavior that ignored indexed property
updates in favor of a panic. While we don't implement persistence
for partial updates, some consumers rely on this behavior to test property
collector updates on specific fields.

This change reverts a03f4735570027d2e6e2bc9cb7584a0af19f9353q to the
previous behavior allowing downstream consumers to rely on this field
for testing PC updates until full support for indexed fields is
implemented.

Closes #3349

vim25/mo/retrieve.go

@@ -77,7 +77,11 @@ func ApplyPropertyChange(obj Reference, changes []types.PropertyChange) {
 	for _, p := range changes {
 		rv, ok := t.props[p.Name]
 		if !ok {
-			panic(p.Name + " not found")
+			// For now, skip unknown properties allowing PC updates to be triggered
+			// for partial updates (e.g. extensionList["my.extension"]).
+			// Ultimately we should support partial updates by assigning the value
+			// reflectively in assignValue.
+			continue
 		}
 
 		assignValue(v, rv, reflect.ValueOf(p.Val))